Get current logged in user from SharePoint and filter DataTable with it

I draw DataTable in successFunction using data from ajax call:

function loadListItems() {
        var oDataUrl = _spPageContextInfo.webAbsoluteUrl + "/_api/web/lists/getbytitle('orders')/items?$select=ID,Title";
        $.ajax({
                url: oDataUrl,
                type: "GET",
                dataType: "json",
                headers: {
                        "accept": "application/json;odata=verbose"
                },
                success: successFunction,
                error: errorFunction
        });
        
}

I get current SP user with this code:

var userid= _spPageContextInfo.userId;
var requestUri = _spPageContextInfo.webAbsoluteUrl + "/_api/web/getuserbyid(" + userid + ")";
var requestHeaders = { "accept" : "application/json;odata=verbose" };
$.ajax({
url : requestUri,
contentType : "application/json;odata=verbose",
headers : requestHeaders,
success : onSuccess,
error : onError
});
function onSuccess(data, request){
var user = data.d.Title;
console.log(user);
}
function onError(error) {
console.log("error");
}

Now how to draw a table and use this user var in table search?

$('#example').DataTable({
    search: {search: user}
});

I guess I need to combine these two ajax calls into one and then use this user var but not sure how to do it.